Thank you for getting in touch with us for the answer of your query. A person with full discretionary powers to act on behalf of a country is known as Plenipotentiary. So, option D is the correct answer. Plenipotentiary is derived from the Latin words, plenus + potens which means full and powerful. As a noun, it refers to a person who has full powers. I hope this makes sense to you and this answer will be helpful for you.
